How many signals would you expect in the ¹³C NMR spectrum of each molecule shown? (c)

Verified step by step guidance

1. Identify the molecule structure: Begin by examining the molecular structure provided in the problem. Look for symmetry and identical carbon environments.
2. Determine unique carbon environments: Analyze the structure to identify unique carbon environments. Carbons in identical environments will produce the same signal in the ¹³C NMR spectrum.
3. Consider symmetry: Check for any symmetry in the molecule, as symmetrical molecules often have fewer unique carbon environments.
4. Count the unique carbon environments: Once you have identified all unique carbon environments, count them. This number corresponds to the number of signals in the ¹³C NMR spectrum.
5. Review and verify: Double-check your analysis to ensure that all unique carbon environments have been accounted for and that no symmetry or identical environments have been overlooked.

Key Concepts

Nuclear Magnetic Resonance (NMR) Spectroscopy

NMR spectroscopy is a powerful analytical technique used to determine the structure of organic compounds. It exploits the magnetic properties of certain nuclei, such as carbon-13 (¹³C), to provide information about the number and environment of carbon atoms in a molecule. The resulting spectrum displays signals corresponding to different carbon environments, allowing chemists to infer structural details.

Chemical Environment

The chemical environment refers to the unique surroundings of a specific atom within a molecule, which can influence its NMR signal. Factors such as electronegativity of nearby atoms, hybridization, and molecular symmetry affect the chemical shift observed in the NMR spectrum. Understanding these influences is crucial for predicting the number of distinct signals in a ¹³C NMR spectrum.

Signal Counting in NMR

In ¹³C NMR spectroscopy, each unique carbon environment typically corresponds to a distinct signal in the spectrum. To count signals accurately, one must consider factors like symmetry and equivalent carbons, which can lead to overlapping signals. Recognizing these patterns is essential for determining the number of signals expected for a given molecule.